1. Field of the Invention
The present invention relates to an apparatus for automatically analyzing trace components contained in biological samples (specimens) such as blood, serum, plasma or urine, and more particularly to an automated analyzer for analyzing the trace components in such specimens either biochemically or immunologically.
2. Description of the Related Art
In the field of clinical diagnosis, the use of analyzers for detecting specific components in a specimen collected from a subject and determining the concentration thereof, and then making a diagnosis of an illness or disease based on the results of this analysis has become widespread. These analyzers include multichannel biochemical analyzers which use enzyme reactions and other chemical reactions to analyze sugars, fats, proteins, and the like, and multichannel immunochemical analyzers that use specific interactions between antigens and antibodies to analyze hormones, tumor markers, and the like.
In order to avoid contamination among the specimens or the reaction fluids, some of these analyzers conduct the biochemical reactions or immunoreactions in individual disposable reaction containers, and in analyzers which use reaction containers that have been pre-filled with the reagents required for analyzing the specified components in the specimen, the use of disposable reaction containers is normal practice.
One example of a known analytical method is enzyme immunoassay (EIA) in which operations are conducted using enzyme labeled antibodies (or antigens). One specific example is known as a sandwich method, in which an antibody (or an antigen), for a specific component to be analyzed, immobilized in a suitable solid phase is used to capture the specific component, an enzyme labeled antibody or antigen (conjugate) is brought in contact to form an immunoreaction complex, any conjugate is removed (by BF separation), and a substrate which utilizes the activity of the enzyme to generate a measurable signal (for example, a variation in light absorbance or a variation in fluorescent intensity) is added. The resulting signal is then measured, the quantity of the enzyme is determined from a prepared calibration curve delineating the relationship between the signal intensity and the enzyme quantity, and this measured enzyme quantity is used to determine the quantity of the specific component being analyzed (see Japanese Patent No. 2,881,826).
In this type of EIA, a variety of different reagents, namely antibodies or antigens, must be used depending on the specific component to be analyzed, and consequently reaction containers containing each of the various reagents and sealed with a sealing member (hereafter described as “reagent cups”) are prepared in advance for each specific component, and the appropriate sealed reagent cups containing the correct reagent are selected and used for each measurement.
An automated analyzer for use with this type of measurement method comprises: a reading device; a sample dispenser; a seal breaker; a BF separator; a substrate dispenser; a detector; and a data analyzer (see Japanese Patent Laid-Open Publication No. 2001-165936). The reading device reads an identification marking made up of symbols, letters and the like, which is printed on the surface of the sealing member covering the reagent cup and indicates the item for analysis. The sample dispenser extracts a specimen of a sample such as blood from a specimen container such as a blood collection tube, and dispenses the specimen into a reagent cup. The seal breaker breaks the sealing member on the reagent cup to open the upper surface of the cup so that the sample can be dispensed into the reagent cup by the above sample dispenser. The BF separator separates and removes (by BF separation) enzyme labeled antibodies that exist in a liquid phase state in the sample-containing reaction fluid in the reagent cup into which the sample has been dispensed. The substrate dispenser adds a substrate for the labeled enzyme to the reagent cup following completion of the BF separation. The detector detects the level of fluorescence, light absorbance, light emission, or the like, which is used for measuring the labeled enzyme activity in the reagent cup after a predetermined length of time following dispensing of the substrate by the substrate dispenser. The data analyzer confirms the existence of, or determining the concentration of, a specific substance based on the signal intensity of the signal detected by the detector, which correlates with the existence of, or the concentration of, the specific substance.
In the case of heterogeneous sandwich EIA analysis using an enzyme for labeling, the reagent cup contains water insoluble magnetizable beads containing an immobilized antibody that undergoes a distinctive bonding with the specific substance, and an enzyme labeled antibody that undergoes a distinctive bonding with the specific substance, which are in a freeze-dried state.
In those cases where, as described above, magnetizable beads are placed in the reagent cups, by positioning a plurality of magnets, with the magnetic poles in an alternating arrangement, on a movable magnet plate that can move back and forth along the direction of movement of the reagent cups, and then moving this movable plate back and forth, the magnetizable beads in the reagent cups can be moved, enabling a stirring action to be initiated inside the reagent cups (see Japanese Patent Publication No. Hei 6-28594).
A conventional automated analyzer described above is also equipped with a transport device, which comprises a specimen container transport system that uses a chain conveyor or the like to move a plurality of the specimen containers in an endless manner, and a reagent cup transport system that uses a chain conveyor or the like to move a plurality of the reagent cups in an endless manner. The analyzer is configured so that when the specimen container transported by the specimen container transport system reaches a defined dispensing position, a predetermined quantity of the specimen is dispensed into a corresponding reagent cup that has been transported into position by the reagent cup transport system.
Because of the requirement to provide two separate transport systems, namely the specimen container transport system and the reagent cup transport system, the analyzer tends to be quite large.
Furthermore, by extending the length of the chain conveyors in the reagent cup transport system, the number of different reagent cups that can be provided for analyzing a single specimen can be increased, but such lengthening of the conveyor causes a corresponding increase in the heat capacity of the reagent cup transport system, which in turn increases the time required to adjust the temperature of the system to the predetermined operating temperature, thereby increasing the time between switching the analyzer on and beginning actual analysis.
Consequently, especially in those cases where rapid analysis is required, it is desirable that the analyzer is available for use as soon as possible after switching the apparatus on.